Industrial gas turbine engines are designed for producing mechanical or electrical power. After a certain operating time, e.g. after a repair or overhaul, test sequences under which the gas turbine engines run with predefined operating points have to be conducted in order to check if the industrial gas turbine engine runs still correctly. Each operating point specifies a set of set points representing the state the engine should be run at.
In conventional industrial gas turbine engines, a test sequence of a gas turbine engine is initiated manually. The operator controls the industrial gas turbine engine by a control device manually, such that the gas turbine engine runs with predetermined set points which are predefined by a test cycle. The predefined test cycle is for example generated in verification or performance tests of the industrial gas turbine engine.
Hence, in order to conduct a test sequence of the industrial gas turbine engine, operators are necessary which initiate and control the test cycles manually. Furthermore, the test sequence which is predetermined under verification tests does often not coincide with the measured operating parameters values and environmental parameters to which the gas turbine engine is exposed in reality. Some of the reasons for this deviation can be found in differences in climate (e.g. temperature or elevation) and fuel composition between where the industrial gas turbine is tested and where it is used on a daily basis.
U.S. Pat. No. 4,821,217 discloses a programmable test station which performs automatically static tests of electrical and pneumatic systems of jet aircraft engines. The test station automatically stimulates the systems to be tested on each engine and measures their response. A programmable data acquisition computer controls both, stimuli and measurements and generates data. The station is operatively connected to a plurality of engines simultaneously and tests certain systems on each in accordance with station user commands.
U.S. Pat. No. 4,389,710 discloses a test circuitry for exercising and testing the operability of antiskid and automatic braking control circuits in an aircraft braking system. A digital processor communicates with an interface circuit associated with each antiskid control circuit and the automatic braking system valve drivers. Each such interface circuit includes an analog switch receiving an electrical stimulus from the processor and applying the same to various test points in the associated antiskid control circuit or automatic braking system valve drivers. An analog selector is connected to various test points in the antiskid control circuits and automatic braking system valve drivers to sense the responses to the electrical stimulus and to pass such responses to the processor to determine the operability of the antiskid and automatic braking control systems.
U.S. Pat. No. 5,521,824 discloses an engine test apparatus using lead-lag control. An operating interface produces a control mode signal and a plurality of set points. The operators also include a test controller for receiving the control mode signal and the plurality of set points and responsively operating the engine test apparatus. The test controller senses operating characteristics of the engine test apparatus. The test controller also selectively operates engine test apparatus parameters in accordance with the control mode signal.
U.S. Pat. No. 8,161,806 discloses a method for monitoring engine performance parameters of a gas turbine engine of an aircraft during its operation. The method includes sensing the performance parameters and generating analog sensor outputs and producing digital data by conditioning the analog sensor outputs with at least one hub unit that is mounted close to an engine.
U.S. Pat. No. 4,215,412 discloses a real-time performance monitoring of gas turbine engines of an aircraft. The monitoring system includes a digital processor that utilizes a set of scalar coefficients and the current value of various engine operating parameters to predict the current value of a set of engine performance parameters. The actual values of these performance parameters are monitored and compared with the predicted values to supply deviation of aero signals to monitoring logic which provides an indication of faults with the digital processor.
EP 1 288 644 discloses a diagnostic method and a diagnostic system for turbine engines. The system evaluates whether faults detected during the testing of a gas turbine engine are related to the performance problems of the engine or to some other abnormality unrelated to engine performance. One performance parameter of the engine is evaluated under one performance condition to generate a first set of current engine data that is then compared to a first set of prior engine data to determine if there is an abnormality.
EP 2 175 336 A1 describes a method for monitoring of the performance of a gas turbine engine over a period of time and compensating for degradation experienced during that extended operation in order to maintain the most satisfactory performance.
EP 2 249 004 A2 describes a method and systems for automatically controlling the thrust output of a gas turbine engine to compensate for deterioration that may occur over time.
EP 2 175 336 A1 and EP 2 249 004 A2 each disclose predictive models which, based on the engine inlet conditions and a reference parameter such as the fuel input, calculate the performance that would be achieved by a nominal or reference engine. Measurements from the operating engine are then compared to equivalent predicted parameters from the model and used as a basis for adjusting one or more control parameters such as fuel system gains or pressure ratio limits etc.